This paper describes a new agent framework that fuses an HTN planner, through its underlying conceptual model, with the mental attitudes of the BDI agent architecture, thus exploiting the strengths of each. On the one hand, the practical and proven ability to reason about actions that is the strength of HTN planning fleshes out the option generation function in the inference loop of the BDI model; on the other hand, the mental attitudes make explicit the knowledge that plays an essential role in plan selection, an important aspect that is not considered in the traditional formulation of the planning problem. The result is a coherent framework that allows for the design and implementation of activity-centric rational agents.